Everybody loves to travel across the globe to different countries. Going on a vacation is one thing, but living in a city is a totally different thing. When shifting to a new place, you must consider how expensive it is to live in that city and what makes them so expensive. Here we give you a list of five most expensive cities to reside in.

1. MoscowMoscow is the capital and the largest city of Russia. It is a major political, cultural, economic, financial and educational centre in Russia and across the world too. Moscow city's economy is strengthened through the oil business and it is home to the largest number of billionaires. The housing rent and the real estate property is extremely high and this makes it one the most expensive cities to live in.

2. LondonLondon is the capital of England and the United Kingdom. It is one of the world's largest financial centres and houses more than 100 of Europe's largest business companies. It is a major tourist destination and London Heathrow Airport is one of the world's busiest airports due to the sheer number of international passengers. Over the years the cost of living in London has skyrocketed due to the hike in the prices of essential commodities, boom in the real estate industry and due to the 2012 Olympics which will be held there.

3. SeoulThe capital of South Korea, Seoul is one of the leading players in business, international trade and technology in the world. It is one of the world's top ten financial and commercial centers and houses some of the biggest companies like Samsung, LG, Hyundai-Kia. Seoul is the 2010 World Design Capital and has one of the world's most technologically advanced infrastructures. All this has made it one of the most expensive cities to reside in.

4. TokyoIt is one of the 47 prefectures of Japan and has the world's largest metropolitan economy. It is considered an alpha + world city and is also considered to be one of the most expensive cities to live in. It is known for its shopping and trading which makes it a popular tourist city. It has top notch infrastructure, first rate transport network, some of the top business companies are situated here and it is also the hub for publishing and broadcasting industries.

5. OsloOslo is the capital of Norway and also one of the largest cities in the country. It is the hub of Norwegian trade as well as cultural and economic growth. It gets its income from a number of thriving sectors like maritime engineering, insurance and tourism. Oslo city has one of the highest average wages, an extremely high tax rate and its essential commodities like foodstuffs are imported, making the cost of living in this city extremely expensive.

Although these cities are some of the most expensive in the world, they offer a qualitative and high standard of living to people from all over the world.

Adivasis, which literally means 'original inhabitants' are believed to be an indigenous populace who make up a whopping 8.2% of Indian population. They are part of different tribes spread all over the country and have specific attributes as part of their culture that makes them different.

Let's take a look at 5 of the most unique and primitive tribes of India and their peculiarities.

1. Dongria Kandh - Orissa

This is a highly endangered tribe that worships 'Niyamgiri Mountain' situated in Kalahadi district in Orissa. They share a unique relationship with this mountain, as forests around this mountain have provided sustenance to this tribe with its water streams, fruits, medicinal herbs and so on for years. A British mining company had to face stiff resistance from these tribes when it wanted to mine out bauxite from their sacred hill.

2. Zekhring - Arunachal Pradesh

The tribe living on the banks of Lohit River on Indo-china border consists of only 300 people who live in one isolated village. The unique aspect about this tribe is its number. It may increase once the tribesmen start marrying out of their tribe but this process would slowly put an end to Zekhring as a separate tribe.

3. Sentinelese - Andaman Islands

These are aboriginal people inhabiting in the North Sentinel Island in the Bay of Bengal. They strongly resist mingling with other people and are very hostile to intruders. They are primitive style hunters and gatherers, indulge in no agricultural practices and wear leaves and other fibers as clothing. In their lifestyle, they literally represent the humans from the Stone Age.

4. Uchalya - Maharashtra

This nomadic tribe of Maharashtra is considered to be a tribe of thieves. For ages, members of this tribe, including women, have indulged in stealing to earn a livelihood. They were rejected in the Hindu caste system and were branded as a criminal community by the Britishers. This reputation restricts them from gaining jobs even today and hence they continue to steal to make ends meet.

5. Bnei Menashe- Mizoram

They are a group of tribes in Mizoram who claim to be one of the '10 lost tribes', which according to a legend, disappeared from Israel some 3000 years ago. The lost tribes were exiled Jews from ancient Judea and Samaria. It is believed that one of the tribes crossed Middle East, Europe and Asia and ended up in isolated regions of Northeast India.

All these 5 tribes form a distinct part of Indian culture and add to the colour and diversity of the country. However, some of these precious tribes are now becoming extinct.

What is Acid Rain? When harmful gases react with the atmosphere, it produces Acid rain or Acidic precipitation. Sulfur dioxide and Nitrogen oxide reacts with atmospheric components and then falls in the form of rain, snow, fog, mist etc. Acid Rain is considered harmful if it has a ph of less than 7. Generally most rain is slightly acidic as it has a ph of around 5-6. This acid rain is extremely harmful to plants, animals and human beings.

Causes of Acid Rain Acid rains are caused by natural processes when gases are emitted from volcanoes, glaciers, etc. It also occurs due to human activity when harmful gases are emitted from factories, power stations for electricity, harmful emissions from motor vehicles etc.

Effects of Acid Rain These harmful gases affect forests causing the deterioration of plant and animal life. Minerals and nutrients in the soil are often washed away by acid rain which causes weak soil. The harmful chemicals of acid rains also stunt the growth of trees and damage the protective coating of leaves.

Lakes and Rivers too are gravely affected by acid rains. The harmful chemicals are deposited into the water, thereby affecting fish, insects, plants and other aquatic animals. Many fish and plants begin to decline or even die due to these harmful chemicals causing many species to become extinct.

Even buildings and human beings are adversely affected by the harmful chemicals emitted from acid rains.

Solutions to control Acid Rains

1. Factories and Power stations need to reduce harmful emissions into the atmosphere. 2. We need to look for other innovative ways to produce power and energy. 3. The use of motor vehicles needs to be reduced in order to control air pollution. This can be done by reducing the use of private transport and more frequently using public transportation. Walking shorter distances is also a solution. 4. An innovative but expensive method called 'liming' of lakes and rivers can help restore them. In essence, we must get to know all about our earth and the atmosphere. They are ours and we must take all the necessary precautions to protect them.

Rainforests receive extremely high amounts of rainfall, with a minimum annual rainfall of 1750-2000 mm (68 to 78 inches). There are the Tropical rainforests of Congo in Sub Saharan Africa, Amazon rainforests in South America etc. Temperate rainforests can be found in North America, British Columbia Coast and so on.

These rainforests are a natural habitat to nearly two-thirds of the world’s varied species of plants and animals. Thousands of mammals, reptiles, birds, insects and plant life like Fungi, Bromeliads, Buttress Roots etc. find a natural home within rainforests.

Various uses of Rainforests1. Rainforests help to control the environment by producing oxygen and by absorbing carbon dioxide.

2. Many plants in rainforests contain medicinal properties and a large number of medicinal drugs are obtained from it. Scientists have also claimed that rainforest plants have medicinal cures for deadly illnesses like cancer, cardiac problems etc.

3. Huge quantities of Timber, animal meat and other foods are also derived from rainforests.

4. It provides food, clothing and shelter to the natives living here.

5. Rainforests have also become major tourist attractions in many countries.

Importance of saving RainforestsRainforests have shrunk drastically to about half their number due to deforestation. Deforestation occurs due to various reasons like logging, urban development, agricultural clearance, silver and gold mining etc. This in turn has lead to the extinction of thousands of species of plants and animals who have lost their natural habitat. Saving rainforests will also help control Global Warming, a potent environmental disaster faced by the world.

What can we do save Rainforests?1. Recycle and Reuse paper2. Limit the use of electrical gadgets3. Don’t waste water and food 4. Plant trees and plants in your garden5. Don’t buy clothes or other mementos made from endangered animals.

If stringent measures are not takes to save rainforests, by 2030, 80% of rainforests would have vanished, 10% will be in a degraded state and only 10% of rainforests will be left.

As we turn on the AC this summer of 2008 and hope for cooler surrounding in this summer heat, the earth is getting warmer and warmer.

Over the past 50 years the average global temperature has increased at the fastest rate in recorded history. Unless we curb global warming emissions, average temperatures could be 3 to 9 degrees higher by the end of the century.

What is Global Warming: Carbon dioxide and other air pollution that is collecting in the atmosphere like a thickening blanket, trapping the sun's heat and causing the planet to warm up.

Which country is producing the most CO2: United States! Though Americans make up just ABOUT 4 percent of the world's population, they produce 25 percent of the carbon dioxide pollution from fossil-fuel burning -- by far the largest share of any country. Coal-burning power plants and automobiles are the largest sources of CO2 emissions in the US. In fact, the United States emits more carbon dioxide than China, India and Japan, combined. (Source: www.nrdc.org )

Why we should be concerned: Global warming is a complex phenomenon, and its full-scale impacts are hard to predict far in advance. But something to think about is that disruption to habitats is almost inevitable, and this could drive many plant and animal species to extinction. We are part of the food chain, and therefore this could only be the beginning of human extinction!

How you can help: Conserve energy, share cab rides, plant more trees. These are the most simple things you can do and still contribute to keeping the earth cooler and do your bit to prevent hotter summers in every future year to come.